1. Field of the Invention
The present invention relates to an organic electroluminescence device capable of converting electric energy to light and thereby emitting light (which device may hereinafter be called “organic EL device”, “luminescence device”, or “device”), in particular, to an organic electroluminescence device excellent in light emitting property and durability.
2. Description of the Related Art
Today, research and development on various display devices (organic luminescence devices) using organic light-emitting materials are actively performed. Of these devices, organic EL devices can realize luminescence with high luminance at low voltage and therefore are drawing attention as promising display devices.
In recent years, devices have improved efficiency by using a phosphorescent material therefor. As the phosphorescent material, an iridium complex and a platinum complex are known (refer to, for example, U.S. Pat. No. 6,303,238, and International Patent Publication Nos. 00/57676 and 00/70655). Satisfactory durability cannot however be attained even by the technologies disclosed therein.
International Patent Publication No. 02/047440 discloses the use of an organic compound containing a deuterium atom, but it has no description about effects produced by combined use of such an organic compound and a phosphorescence emission metal complex material.
JP-A-2005-48004 (The term “JP-A” as used herein refers to an “unexamined published Japanese patent application”.) discloses the use of a deuterium-containing carbazole material that produces phosphorescence at ordinary temperatures, but it also has no description about effects produced by combined used of such a carbazole material and a phosphorescence emission metal complex material.